Finding the Fourth Proportional to 1,081.27, 1,492.20 and 639.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.27 : 1,492.20 = 639.16 : x
2. Step 2: Convert to fraction form
   1,081.27/1,492.20 = 639.16/x
3. Step 3: Cross multiply
   1,081.27x = 1,492.20 × 639.16
4. Step 4: Simplify right side
   1,081.27x = 953,754.55
5. Step 5: Solve for x
   x = 953,754.55/1,081.27
6. Step 6: Final answer
   x = 882.07